| 3001 | ORJ | Orangecargo, Inc. | Callsign: Orangecargo, Founded on 27 september 2002. Ceased operations on 22 March 2004. | J | AVCODES |
| 3002 | ORJ | Orange Air Sierra Leone Limited | IATA: O5, | WAL | AVCODES |
| 3003 | ORJ | Orange Air Sierra Leone | | | ICAO1 |
| 3004 | ORJH | ORLANDO, JAMES H | | | SCAC3 |
| 3005 | ORK | Orca Air | Callsign: Orca Taxi, | ET | AVCODES |
| 3006 | ORK | Air Orkney | Callsign: Orkney, | GB | AVCODES |
| 3007 | ORK | Orca Air | | | ICAO1 |
| 3008 | ORKC | ONEIL RELOCATION-KANSAS CITY INC | | | SCAC4 |
| 3009 | ORKE | OROURKE TRANSPORT INC | | | SCAC4 |
| 3010 | ORKM | OROURKE MOVERS INCORPORATED | | | SCAC3 |
| 3011 | ORKOL | ORLEN KolTrans Sp. z o.o. | | PL | VKM |
| 3012 | ORKQ | ORORKE TRANSFER | | | SCAC3 |
| 3013 | ORL | On Air Limited | Callsign: On Air, | CDN | AVCODES |
| 3014 | ORL | On Air Limited | | | ICAO1 |
| 3015 | ORL | | City: Orleans | F | TRAFFIC |
| 3016 | ORLC | ORIENTAL LOGISTICS GROUP LIMITED | | | SCAC4 |
| 3017 | ORLEN | Orlen Transport Płock sp. z o.o. | City: Płock | PL | TRAFFIC |
| 3018 | ORLEN | Polski Koncern Naftowy ORLEN S.A. | | PL | VKM |
| 3019 | ORLI | ORLEANS TRUCKING INC | | | SCAC3 |
| 3020 | ORLI | OCEAN RAIL LOGISTICS INC | | | SCAC4 |
| 3021 | ORLK | ORLICK TRANSPORT LTD | | | SCAC3 |
| 3022 | ORLK | ORLICK TRANSPORT | | | SCAC4 |
| 3023 | ORLL | OREILLY, DAN | | | SCAC4 |
| 3024 | ORLM | ONE FOUR FOUR SEVEN THREE ONE ONE ( | | | SCAC4 |
| 3025 | ORLN | ORLANDO ENTERPRISES INC | | | SCAC4 |
| 3026 | ORLP | OWENS, RALPH TRUCKING CO INC | | | SCAC3 |
| 3027 | ORLQ | ORIOLE TERMINAL & TRANSPORTATION | | | SCAC3 |
| 3028 | ORM | Orel State Air Enterprise | Callsign: Orprise, | RUS | AVCODES |
| 3029 | ORM | Orel State Air Enterprise | | | ICAO1 |
| 3030 | ORMA | ORIENTAL MASTER INTERN | | | SCAC3 |
| 3031 | ORMA | ORIENTAL MASTER INTERN | | | SCAC4 |
| 3032 | ORMB | ORMSBY INTERNATIONAL CUSTOMHOUSE BR | | | SCAC3 |
| 3033 | ORMB | OREMBA LIVESTOCK, KELLY HAULING LTD | | | SCAC4 |
| 3034 | ORME | ORMES TRANSPORTATION INC | | | SCAC3 |
| 3035 | ORME | Eisenbahnausrüstung und Zubehör mbH | | DE | VKM |
| 3036 | ORMG | O/R MESSENGER SERVICE INC | | | SCAC3 |
| 3037 | ORML | OCEANREIGN MARINE LIMITED | | | SCAC3 |
| 3038 | ORMM | OMEGA RIGGING & MACHINERY MOVING IN | | | SCAC4 |
| 3039 | ORMQ | ORR, LEONARD MOTOR SERVICE INC | | | SCAC3 |
| 3040 | ORMX | D.L. Orme | 1/1952-10/1966; eliminated 1/1970 | | NAKINA |
| 3041 | ORMX | D.L. Orme | 1/52-10/66; eliminated 1/70 | | NRHS |
| 3042 | ORMX | *D. L. ORME | | | PWRC |
| 3043 | ORMX | *OHIO RAILWAY MUSEUM | | | PWRC |
| 3044 | ORMX | ORME, D L | | | SCAC3 |
| 3045 | ORMX | OHIO RAILWAY MUSEUM | | | SCAC4 |
| 3046 | ORN | Orient Airways | Callsign: Orient Liner, | PK | AVCODES |
| 3047 | ORN | Orion Airways | IATA: KG, Callsign: Orion, Founded in 1979. Merged into Britannia Airways. | GB | AVCODES |
| 3048 | ORN | Orange Air, LLC | IATA: O3, Callsign: Orange Jet, | USA | AVCODES |
| 3049 | ORN | Orient Airways | | | ICAO1 |
| 3050 | ORN | Oregon Railroad and Navigation Company | | USA | TRAFFIC |
| 3051 | ORNB | ORANGEBURG MACHINE WORKS INC | | | SCAC3 |
| 3052 | ORNB | ORION TRANSPORT CORPROATION | | | SCAC4 |
| 3053 | ORNE | ORNELAS RAMIREZ, LUSANA | | | SCAC4 |
| 3054 | ORNE | Orange, Newark, and Elizabeth | | USA | TRAFFIC |
| 3055 | ORNG | ORTIZ YANEZ, JOSE REFUGIO | | | SCAC4 |
| 3056 | ORNK | ORION INTERMODAL TRANSPORTATION COR | | | SCAC4 |
| 3057 | ORNL | ORIENTAL TRUCKING | | | SCAC3 |
| 3058 | ORNT | ORION TRANSPORT INC | | | SCAC3 |
| 3059 | ORNT | ORION TRANSPORT INC | | | SCAC4 |
| 3060 | ORNU | ORANO CYCLE | | F | BIC |
| 3061 | ORO | C N Air, S.A. | Callsign: Capri, Name changed to Clipper National Air, S.A. | E | AVCODES |
| 3062 | ORO | Clipper National Air, S.A. | Callsign: Capri, Name changed from C N Air, S.A. | E | AVCODES |
| 3063 | ORO | C N Air | | | ICAO1 |
| 3064 | ORO | ORIONE S.r.l. | | IT | VKM |
| 3065 | OROB | OROZCO BERISTAIN, MARTHA LETICIA | | | SCAC4 |
| 3066 | OROK | OROURKE STORAGE & TRANSFER CO INC | | | SCAC3 |
| 3067 | ORON | ORION TRUCKING INC | | | SCAC3 |
| 3068 | OROR | O'ROURKE CARTAGE CO | | | SCAC3 |
| 3069 | OROR | OROURKE CARTAGE INC | | | SCAC4 |
| 3070 | OROS | OCEAN ROLL-OFF SERVICES | | | SCAC3 |
| 3071 | OROT | ORION MANAGEMENT CORPORATION | | | SCAC3 |
| 3072 | OROU | AUTOGASERVICE S.R.L. | | I | BIC |
| 3073 | OROX | U.S. Dept. of Energy, Oak Ridge Operations Office | added 1/1978; 1/1980-1/1994; eliminated 7/1995; 7/2000-7/2005 (not listed) | | NAKINA |
| 3074 | OROX | United States Energy Research and Development Administration, Oak Ridge Operations Office | added 4/1975; eliminated 1/1978 | | NAKINA |
| 3075 | OROX | U.S. Atomic Energy Commission, Oak Ridge Operations Office | eliminated 4/1975 | | NAKINA |
| 3076 | OROX | U.S. Atomic Energy Commission | added 10/1969; 4/1970-1/1975 | | NAKINA |
| 3077 | OROX | U.S. Atomic Energy Commission | added 10/69; 4/70-1/75 | | NRHS |
| 3078 | OROX | U.S. Atomic Energy Commission, Oak Ridge Operations Office | eliminated 4/75 | | NRHS |
| 3079 | OROX | United States Energy Research and Development Administration, Oak Ridge Operations Office | added 4/75; eliminated 1/78 | | NRHS |
| 3080 | OROX | U.S. Dept. of Energy, Oak Ridge Operations Office | added 1/78; 1/80-1/94; eliminated 7/95; 7/2000 | | NRHS |
| 3081 | OROX | U.S. DEPART. OF ENERGY - OAK RIDGE OPERATIONS [U.S. ATOMIC ENERGY COMMISSION] | | | PWRC |
| 3082 | OROX | United States Department of Energy Oak Ridge Operations Office | | | RSRV |
| 3083 | ORP | Aerocorp, S.A. de C.V. | Callsign: Corpsa, | MEX | AVCODES |
| 3084 | ORP | Aerocorp | | | ICAO1 |
| 3085 | ORPF | OR PAC FEED & FORAGE LTD | | | SCAC4 |
| 3086 | ORPH | ORPHEAS NAVIGATION INC | | | SCAC4 |
| 3087 | ORPI | OYSTER RIVER PETROLEUM INC | | | SCAC4 |
| 3088 | ORPP | O'ROURKE PETROLEUM PRODUCTS | | | SCAC4 |
| 3089 | ORPQ | OWL ROCK PRODUCTS CO | | | SCAC3 |
| 3090 | ORPT | OREGON PETROLEUM TRANSPORT COMPANY | | | SCAC4 |
| 3091 | ORPU | OJC OCETROVSKIY RIVER PORT | | RUS | BIC |
| 3092 | ORPU | OJC OCETROVSKIY RIVER PORT | | | SCAC4 |
| 3093 | ORPX | O.E. Linsin, Inc. | 7/1937 (not listed) | | NAKINA |
| 3094 | ORPX | Orient Petroleum Co. (Atlantic-Pacific & Gulf Refining Co.) | 7/1932-7/1935 | | NAKINA |
| 3095 | ORPX | Orient Petroleum Co. | 7/1930 | | NAKINA |
| 3096 | ORPX | O.E. LINSIN [ATLANTIC-PACIFIC & GULF REFINING CO.; ORIENT PETROLEUM CO.] | | | PWRC |
| 3097 | ORR | Operadora Turistica Aurora, S.A. de C.V. | Callsign: Turistica Aurora, | MEX | AVCODES |
| 3098 | ORR | Operadora Turistica Aurora | | | ICAO1 |
| 3099 | ORR | Osage R.R. | 1/1994; added 1/1996; eliminated 10/1996; 7/2000-7/2005 | | NAKINA |
| 3100 | ORR | Osage R.R. | 1/94; added 1/96; eliminated 10/96; 7/2000 | | NRHS |
